scholarly journals Functional expression of mammalian glucose transporters in Xenopus laevis oocytes: evidence for cell-dependent insulin sensitivity.

1989 ◽  
Vol 9 (10) ◽  
pp. 4187-4195 ◽  
Author(s):  
J C Vera ◽  
O M Rosen
Keyword(s):  
Glucose Uptake ◽  
Rat Brain ◽  
Xenopus Oocytes ◽  
Glucose Transporter ◽  
Glucose Transporters ◽  
Functional Expression ◽  
Xenopus Laevis Oocytes ◽  
Rat Brain And Liver ◽  
Insulin Responsiveness

We report the functional expression of two different mammalian facilitative glucose transporters in Xenopus oocytes. The RNAs encoding the rat brain and liver glucose transporters were transcribed in vitro and microinjected into Xenopus oocytes. Microinjected cells showed a marked increase in 2-deoxy-D-glucose uptake as compared with controls injected with water. 2-Deoxy-D-glucose uptake increased during the 5 days after microinjection of the RNAs, and the microinjected RNAs were stable for at least 3 days. The expression of functional glucose transporters was dependent on the amount of RNA injected. The oocyte-expressed transporters could be immunoprecipitated with anti-brain and anti-liver glucose transporter-specific antibodies. Uninjected oocytes expressed an endogenous transporter that appeared to be stereospecific and inhibitable by cytochalasin B. This transporter was kinetically and immunologically distinguishable from both rat brain and liver glucose transporters. The uniqueness of this transporter was confirmed by Northern (RNA) blot analysis. The endogenous oocyte transporter was responsive to insulin and to insulinlike growth factor I. Most interestingly, both the rat brain and liver glucose transporters, which were not insulin sensitive in the tissues from which they were cloned, responded to insulin in the oocyte similarly to the endogenous oocyte transporter. These data suggest that the insulin responsiveness of a given glucose transporter depends on the type of cell in which the protein is expressed. The expression of hexose transporters in the microinjected oocytes may help to identify tissue-specific molecules involved in hormonal alterations in hexose transport activity.

Functional expression of mammalian glucose transporters in Xenopus laevis oocytes: evidence for cell-dependent insulin sensitivity

1989 ◽  
Vol 9 (10) ◽  
pp. 4187-4195
Author(s):  
J C Vera ◽  
O M Rosen
Keyword(s):  
Glucose Uptake ◽  
Rat Brain ◽  
Xenopus Oocytes ◽  
Glucose Transporter ◽  
Glucose Transporters ◽  
Functional Expression ◽  
Xenopus Laevis Oocytes ◽  
Rat Brain And Liver ◽  
Insulin Responsiveness

We report the functional expression of two different mammalian facilitative glucose transporters in Xenopus oocytes. The RNAs encoding the rat brain and liver glucose transporters were transcribed in vitro and microinjected into Xenopus oocytes. Microinjected cells showed a marked increase in 2-deoxy-D-glucose uptake as compared with controls injected with water. 2-Deoxy-D-glucose uptake increased during the 5 days after microinjection of the RNAs, and the microinjected RNAs were stable for at least 3 days. The expression of functional glucose transporters was dependent on the amount of RNA injected. The oocyte-expressed transporters could be immunoprecipitated with anti-brain and anti-liver glucose transporter-specific antibodies. Uninjected oocytes expressed an endogenous transporter that appeared to be stereospecific and inhibitable by cytochalasin B. This transporter was kinetically and immunologically distinguishable from both rat brain and liver glucose transporters. The uniqueness of this transporter was confirmed by Northern (RNA) blot analysis. The endogenous oocyte transporter was responsive to insulin and to insulinlike growth factor I. Most interestingly, both the rat brain and liver glucose transporters, which were not insulin sensitive in the tissues from which they were cloned, responded to insulin in the oocyte similarly to the endogenous oocyte transporter. These data suggest that the insulin responsiveness of a given glucose transporter depends on the type of cell in which the protein is expressed. The expression of hexose transporters in the microinjected oocytes may help to identify tissue-specific molecules involved in hormonal alterations in hexose transport activity.

Functional Expression of Sodium-Dependent Glucose Transporter in Amelogenesis

2020 ◽  
Vol 99 (8) ◽  
pp. 977-986
Author(s):  
H. Ida-Yonemochi ◽  
K. Otsu ◽  
H. Harada ◽  
H. Ohshima
Keyword(s):  
Organ Culture ◽  
Glucose Uptake ◽  
Glucose Transport ◽  
Glucose Transporter ◽  
Glucose Transporters ◽  
Maturation Stage ◽  
Sodium Dependent ◽  
Tooth Morphogenesis

Glucose is an essential source of energy for mammalian cells and is transported into the cells by glucose transporters. There are 2 types of glucose transporters: one is a passive glucose transporter, GLUT ( SLC2A), and the other is a sodium-dependent active glucose transporter, SGLT ( SLC5A). We previously reported that the expression of GLUTs during tooth development is precisely and spatiotemporally controlled and that the glucose uptake mediated by GLUT1 plays a crucial role in early tooth morphogenesis and tooth size determination. This study aimed to clarify the localization and roles of SGLT1 and SGLT2 in murine ameloblast differentiation by using immunohistochemistry, immunoelectron microscopy, an in vitro tooth organ culture experiment, and in vivo administration of an inhibitor of SGLT1/2, phloridzin. SGLT1, which has high affinity with glucose, was immunolocalized in the early secretory ameloblasts and the ruffle-ended ameloblasts in the maturation stage. However, SGLT2, which has high glucose transport capacity, was observed in the stratum intermedium, papillary layer, and ameloblasts at the maturation stage and colocalized with Na+-K+-ATPase. The inhibition of SGLT1/2 by phloridzin in the tooth germs induced the disturbance of ameloblast differentiation and enamel matrix formation both in vitro (organ culture) and in vivo (mouse model). The expression of SGLT1 and SGLT2 was significantly upregulated in hypoxic conditions in the ameloblast-lineage cells. These findings suggest that the active glucose uptake mediated by SGLT1 and SGLT2 is strictly regulated and dependent on the intra- and extracellular microenvironments during tooth morphogenesis and that the appropriate passive and active glucose transport is an essential event in amelogenesis.

scholarly journals Comparative study of expression and activity of glucose transporters between stem cell-derived brain microvascular endothelial cells and hCMEC/D3 cells

2017 ◽  
Vol 313 (4) ◽  
pp. C421-C429 ◽  
Author(s):  
Abraham J. Al-Ahmad
Keyword(s):  
Stem Cells ◽  
Endothelial Cells ◽  
Glucose Uptake ◽  
Glucose Transporter ◽  
Glucose Transporters ◽  
Microvascular Endothelial Cells ◽  
Brain Microvascular Endothelial Cells ◽  
Glucose Transporter 1 ◽  
Microvascular Endothelial

Glucose constitutes a major source of energy of mammalian brains. Glucose uptake at the blood-brain barrier (BBB) occurs through a facilitated glucose transport, through glucose transporter 1 (GLUT1), although other isoforms have been described at the BBB. Mutations in GLUT1 are associated with the GLUT1 deficiency syndrome, yet none of the current in vitro models of the human BBB maybe suited for modeling such a disorder. In this study, we investigated the expression of glucose transporters and glucose diffusion across brain microvascular endothelial cells (BMECs) derived from healthy patient-derived induced pluripotent stem cells (iPSCs). We investigated the expression of different glucose transporters at the BBB using immunocytochemistry and flow cytometry and measured glucose uptake and diffusion across BMEC monolayers obtained from two iPSC lines and from hCMEC/D3 cells. BMEC monolayers showed expression of several glucose transporters, in particular GLUT1, GLUT3, and GLUT4. Diffusion of glucose across the monolayers was mediated via a saturable transcellular mechanism and partially inhibited by pharmacological inhibitors. Taken together, our study suggests the presence of several glucose transporters isoforms at the human BBB and demonstrates the feasibility of modeling glucose across the BBB using patient-derived stem cells.

Interleukin-1β Stimulates Glucose Uptake of Human Peritoneal Mesothelial Cells In Vitro

1996 ◽  
Vol 16 (1_suppl) ◽  
pp. 58-60 ◽  
Author(s):  
Michael Kruse ◽  
Arezki Mahiout ◽  
Volker Kliem ◽  
Peter Kurz ◽  
Karl-Martin Koch ◽  
...  
Keyword(s):  
Glucose Uptake ◽  
Glucose Transporter ◽  
Cytochalasin B ◽  
Interleukin 1 ◽  
Glucose Transporters ◽  
Mesothelial Cells ◽  
Dependent Manner ◽  
Peritoneal Mesothelial Cells ◽  
Human Peritoneal Mesothelial Cells

To investigate whether the glucose uptake (GU) of human peritoneal mesothelial cells (HPMC) is mediated by glucose transporters and whether this uptake is influenced by interleukin 1–β (IL-1β), we measured 2-deoxy-(3H)-GU of HPMC in vitro, after exposing the cells for different times (two and 12 hours) to increasing concentrations (0.1, 1.0, and 2.0 ng/mL) of IL-1 β. To exclude a noncarrier-mediated transport, GU was also tested in the presence of cytochalasin B. All experiments were performed in triplicate in the cells of two donors. Cytochalasin B inhibits GU of HPMC almost completely. GU of HPMC is not stimulated by insulin. GU is stimulated by IL-1 β in a dose-dependent manner. These data indicate a GU of HPMC, which is mediated by a glucose transporter and stimulated by IL-1 β. The increased uptake of glucose from the dialysate In patients with peritonitis may be mediated by a (cytokineinduced) increased activity of HPMC glucose transporters.

scholarly journals Identification and characterisation of two high-affinity glucose transporters from the spoilage yeast Brettanomyces bruxellensis

2019 ◽  
Vol 366 (17) ◽  
Author(s):  
Ievgeniia A Tiukova ◽  
Iben Møller-Hansen ◽  
Zeinu M Belew ◽  
Behrooz Darbani ◽  
Eckhard Boles ◽  
...  
Keyword(s):  
Glucose Transport ◽  
Glucose Transporter ◽  
Glucose Transporters ◽  
Xenopus Laevis Oocytes ◽  
Yeast Saccharomyces Cerevisiae ◽  
Brettanomyces Bruxellensis ◽  
High Affinity ◽  
Spoilage Yeast ◽  
Uptake Rates

ABSTRACT The yeast Brettanomyces bruxellensis (syn. Dekkera bruxellensis) is an emerging and undesirable contaminant in industrial low-sugar ethanol fermentations that employ the yeast Saccharomyces cerevisiae. High-affinity glucose import in B. bruxellensis has been proposed to be the mechanism by which this yeast can outcompete S. cerevisiae. The present study describes the characterization of two B. bruxellensis genes (BHT1 and BHT3) believed to encode putative high-affinity glucose transporters. In vitro-generated transcripts of both genes as well as the S. cerevisiae HXT7 high-affinity glucose transporter were injected into Xenopus laevis oocytes and subsequent glucose uptake rates were assayed using 14C-labelled glucose. At 0.1 mM glucose, Bht1p was shown to transport glucose five times faster than Hxt7p. pH affected the rate of glucose transport by Bht1p and Bht3p, indicating an active glucose transport mechanism that involves proton symport. These results suggest a possible role for BHT1 and BHT3 in the competitive ability of B. bruxellensis.

scholarly journals Differential regulation of two distinct families of glucose transporter genes in Trypanosoma brucei.

1993 ◽  
Vol 13 (2) ◽  
pp. 1146-1154 ◽  
Author(s):  
F Bringaud ◽  
T Baltz
Keyword(s):  
Trypanosoma Brucei ◽  
Xenopus Oocytes ◽  
Glucose Transporter ◽  
Protein S ◽  
Life Cycle Stage ◽  
Good Target ◽  
Hexose Transporters ◽  
Moderate Sensitivity ◽  
Mrna Analysis

A tandemly arranged multigene family encoding putative hexose transporters in Trypanosoma brucei has been characterized. It is composed of two 80% homologous groups of genes called THT1 (six copies) and THT2 (five copies). When Xenopus oocytes are microinjected with in vitro-transcribed RNA from a THT1 gene, they express a glucose transporter with properties similar to those of the trypanosome bloodstream-form protein(s). This THT1-encoded transport system for glucose differs from the human erythrocyte-type glucose transporter by its moderate sensitivity to cytochalasin B and its capacity to transport D-fructose. These properties suggest that the trypanosomal transporter may be a good target for antitrypanosomal drugs. mRNA analysis revealed that expression of these genes was life cycle stage dependent. Bloodstream forms express 40-fold more THT1 than THT2. In contrast, procyclic trypanosomes express no detectable THT1 but demonstrate glucose-dependent expression of THT2.

scholarly journals Antihyperglycemic and Antilipidemic Effects of the Ethanol Extract Mixture of Ligularia fischeri and Momordica charantia in Type II Diabetes-Mimicking Mice

2018 ◽  
Vol 2018 ◽  
pp. 1-15
Author(s):  
Hyun Jin Baek ◽  
Yong Joon Jeong ◽  
Jeong Eun Kwon ◽  
Jong Sung Ra ◽  
Sung Ryul Lee ◽  
...  
Keyword(s):  
Glucose Uptake ◽  
Uptake Rate ◽  
Glucose Transporter ◽  
Synergistic Effects ◽  
Momordica Charantia ◽  
C2c12 Cells ◽  
Peroxisome Proliferator ◽  
Glucose Uptake Rate ◽  
Ligularia Fischeri

The extract of the Momordica charantia fruit (MCE) is recognized as an alternative treatment for diabetes. The extract of Ligularia fischeri leaves (LFE) is traditionally used as a folk medicine for treating inflammatory diseases in Korea as well. In this study, we investigated the synergistic effect of MCE combined with LFE on antihyperglycemic and antihyperlipidemic potentials. Based on the α-glucosidase inhibitory effect and promotion of adipocyte differentiation in the 3T3-L1 cell line, the MLM was prepared with MCE:LFE (8:2 weight:weight). MLM showed the synergistic effects in the promotion of the glucose uptake rate, suppression of dipeptidyl peptidase-4 (DPP-4) mRNA expression, upregulation of an insulin receptor substrate and glucose transporter type-4 expression, and an increase in insulin-associated signaling in C2C12 cells. In addition, the efficacy of peroxisome proliferator-activated receptor-γ agonism and glucose uptake rate by MLM supplementation was significantly enhanced in vitro. Then, the antihyperglycemic and antihyperlipidemic effects of MCE, LFE, and MLM at the dose of 50, 100, and 200 mg/kg/day (n = 6 per each group) were determined in streptozotocin (STZ)-insulted mice fed an atherogenic diet (ATH) for 4 weeks. In addition, MLM (50, 100, and 200 mg/kg/day, n = 5 per each group) was supplemented in ATH-fed db/db mice for 10 weeks. Compared with MCE or LFE alone, MLM supplementation led to a more significant reduction of glucose levels in both STZ/ATH and db/db/ATH mice as well as lowered lipid profiles in STZ/ATH mice. In addition, the stimulation of islet of Langerhans regeneration was more pronounced by MLM supplementation in both mice models. In conclusion, antihyperglycemic and antihyperlipidemic effects were strengthened by the combined extracts of L. fischeri and M. charantia (MLM) in diabetes-mimicking mice.

scholarly journals A possible role for a mammalian facilitative hexose transporter in the development of resistance to drugs.

1991 ◽  
Vol 11 (7) ◽  
pp. 3407-3418 ◽  
Author(s):  
J C Vera ◽  
G R Castillo ◽  
O M Rosen
Keyword(s):  
Xenopus Oocytes ◽  
Glucose Transporter ◽  
Cytochalasin B ◽  
Chinese Hamster ◽  
Multidrug Resistant ◽  
Xenopus Laevis Oocytes ◽  
Hexose Transporter ◽  
P Glycoprotein ◽  
Glut1 Protein ◽  
Facilitative Glucose Transporter

We show that D- but not L-hexoses modulate the accumulation of radioactive vinblastine in injected Xenopus laevis oocytes expressing the murine Mdr1b P-glycoprotein. We also show that X. laevis oocytes injected with RNA encoding the rat erythroid/brain glucose transport protein (GLUT1) and expressing the corresponding functional transporter exhibit a lower accumulation of [3H]vinblastine and show a greater capacity to extrude the drug than do control oocytes not expressing the rat GLUT1 protein. Cytochalasin B and phloretin, two inhibitors of the mammalian facilitative glucose transporters, can overcome the reduced drug accumulation conferred by expression of the rat GLUT1 protein in Xenopus oocytes but have no significant effect on the accumulation of drug by Xenopus oocytes expressing the mouse Mdr1b P-glycoprotein. These drugs also increase the accumulation of [3H]vinblastine in multidrug-resistant Chinese hamster ovary cells. Cytochalasin E, an analog of cytochalasin B that does not affect the activity of the facilitative glucose transporter, has no effect on the accumulation of vinblastine by multidrug-resistant Chinese hamster cells or by oocytes expressing either the mouse Mdr1b P-glycoprotein or the GLUT1 protein. In all three cases, the drug verapamil produces a profound effect on the cellular accumulation of vinblastine. Interestingly, although immunological analysis indicated the presence of massive amounts of P-glycoprotein in the multidrug-resistant cells, immunological and functional studies revealed only a minor increase in the expression of a hexose transporter-like protein in resistant versus drug-sensitive cells. Taken together, these results suggest the participation of the mammalian facilitative glucose transporter in the development of drug resistance.

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